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Verification Regulation of Digital Pressure Gauge
JJC:875-1994
Verification Regulation of Digital Pressure Gauge
JJG 875—1994 3
This calibration standard was approved on April 5, 2014 and implemented on December 1, 2014. Responsible unit: Shanghai Technical Supervision Office
Drafting unit: Shanghai Zhongxi County Building Technology Research Institute Shanghai Control and Measurement Technology Institute
The issuing unit of the technical provisions of this standard is responsible for the interpretation of the main drafters of this standard:
Huang Huayuan
(Shanghai Basic Technology Research Institute)
?Shanghai Testing Technology Institute
(Shanghai Measurement Technology Research Institute)
Wu Zengyao
Participating drafter:
(Shanghai Measurement Technology Research Institute)
Technical Practice
National calibration item date and calibration results group and calibration cycle
Appendix 1 Number! Subtotal calibration record format
Appendix 2: Verification certificate format
Appendix 5: Verification result notification format
Digital pressure gauge calibration procedure
This document is applicable to newly manufactured, in-use and adjusted digital pressure gauges: (The following pressure gauges) The digital pressure gauges can be calibrated according to this document. The digital pressure gauge uses a digital pressure sensor to display the pressure value. The working principle is as follows: the measured force is sensed by the pressure sensor, and if the force changes, the force sensor will output a corresponding electrical signal, which is also processed by the signal and then displayed at the end: the measured value is displayed. The working principle is as shown in Figure 1 - Digital pressure gauge is used to measure pressure. In small measurements, the digital pressure gauge can be divided into two types: integer type: The pressure sensor and the digital display are combined into a whole: A pressure sensor can be integer or integer type. Three technical requirements: I. Appearance: 1.1 The structure of the dynamometer should be firm, intact and new. The dynamometer should be shiny and without any exposed layers or scratches. 1.2 The switches, knobs and other functional components and connecting (finger) parts on the pressure gauge should not be loose or damaged. 1.3 The digital display plate of the dynamometer should not have any defects. 1.4 The inscription on the dynamometer should be clearly marked with the product name, model, measuring method, accuracy and grade, unit of measurement, manufacturer name or prefix, and serial number and year and month of production. 【, S\Absolute pressure is the full-pressure pressure. The panel should be marked with an absolute sign. 1. The dynamometer should have a terminal (H) for prohibiting measurement, a low-pressure terminal (H) for medium and low-pressure, and a reduced-pressure display. 2.1 After the pressure gauge is disconnected from the power supply, the digital display 1 shows the initial value of the small part. 2.2 The pressure gauge is turned off and the power supply is turned off. The numbers displayed on the display show continuous changes, and the lines are not in line with the strokes. The decimals are set to zero position. The table method is used. The positive drift of the dynamometer zero is not allowed to be checked. The accuracy level of the absolute value is shown in the table. The accuracy of the pressure indication is allowed. See the table. 5. The design error of the pressure gauge is not greater than the absolute value of the dynamometer. Use the zero position error
accuracy data to complete the recognition (as a percentage of the required process): .05
The non-static pressure error should not be greater than the allowable error of the gauge: The absolute value of the voltage difference should not be less than 2(M2-) of the source resistance of the machine. The additional energy required by the function
pressure can be gradually increased. Its technical indicators are gradually required. Three verification conditions
Inspection and installation
9.1 Standard instrument
Standard instrument is sent back as follows: For pressure gauges with an accuracy level of 0.1, 0.2, .5, and 1, the allowable error value of the selected standard instrument should be less than the allowable error value of the pressure gauge: For pressure levels with an accuracy level of U.S., the standard can be selected according to the calibration system. When selecting a standard flowmeter, it can be based on The accuracy level and measurement range of pressure gauges shall be selected from the following standard instruments: "Pressure gauges as reference: standard micrometers, standard piston gauges, thrust force vacuum gauges, gas pressure gauges, standard spherical pressure gauges, standard wave pressure gauges. Precision pressure gauges, digital pressure gauges, etc. 9.2 Auxiliary equipment
Pressure source, vacuum system, one-way check head, pressure guide, pressure transmitter, insulator resistance meter, etc. 10 Verification environment conditions
Oil density, etc. bzxZ.net
0.0531.0 Level
Required accuracy:
241±2
Ambient temperature shall comply with the requirements of Table 2,
relative humidity and humidity greater than 75%
In the inspection environment, the reading shall be recognized by the value 10.3
Or the effectiveness of the calibration can be strengthened, the dynamometer should be adjusted under the calibration conditions. The four calibration items and calibration methods are as follows: appearance inspection and use of dynamometer, which should meet the requirements of the enterprise. 12. When the pressure gauge is connected to the power supply, the start and end values should be shown on the display. The pressure gauge and the dynamometer should display the zero value. The absolute pressure gauge can display the human rate, and then preheat to 0m. The product should be pre-set according to the requirements of the product book. 13. Safety drift inspection: For the gauge pressure or pressure gauge, at the end of the input state, record the maximum value (the dynamometer can be adjusted to the zero value, and the digits can be adjusted to the rate. No adjustment is allowed during the calibration process), and record every 15 minutes! Second indication: about 1h, the absolute difference between each indication value and the initial value should be equal to the first safety requirement, 14 Basic error of indication verification
14.1 Verification device
The given device is composed of a standard instrument, a power source, and a pressure-conducting joint. The pressure gauge is connected with the end of the component, and the connection should not be leaking. The small turbulence is shown in Figure 2. 14.2 Number of calibration points and circulation effect r
Figure: Schematic diagram of calibration equipment
【Standard】 【Worker: 2 Conductor: 5 Two-way joint: 3 Two-way joint: Source
14.3.2 Calibration method for dynamometers
The pressure gauges with accuracy levels of 0.05, 6.1 and 0.2 will have no less than 10 calibration points within the range, and they shall be relatively evenly distributed within the measuring range: The hydraulic gauges with accuracy levels of 5 and 1 shall have no less than 5 calibration points within the range, including the zero point, and they shall be relatively evenly distributed within the measuring range. After two positive and negative stroke cycles, the business will go through two cycles.
14.3 Verification method
14.3, 1 pressure, decompression display check
The dynamometer switches the air source, steadily pressurizes the upper limit, and then steadily depressurizes it to the initial operating state: the number displayed on the display shall meet the requirements of Article 2.2.
Pressure leakage is measured on the pressure gauge and standard instrument from zero point (use liquid as the pressure regulator to remove air in the pipeline first) and slowly and steadily pressurize to the upper limit of measurement, calibrate the indication error of the pre-selected calibration point, and after the pressure at each calibration point is stable, first read the indication on the standard instrument, then collect the positive stroke value of the pressure gauge, start to record, and then, cause a small force fluctuation within the limit, and perform reverse calibration after the pressure stabilizes, slowly and steadily until zero point, and at the same time read the indication on the standard instrument, then take the reverse stroke indication of the pressure gauge, and make a record. The virtual pressure meter that can measure positive or negative pressure should select the correct components for positive and negative pressure. When the standard instrument and the positive pressure reducing body are used as the medium, their pressure points should be at the same level, not on the same horizontal plane, to avoid the pressure measurement error caused by the liquid column and the quality difference. 14.3.3 The calculation formula of the direct basic technical error is as follows:
8-4x 100%
formula: —— pressure test point indication error, Le dynamometer test point positive and negative stroke indication, PA standard instrument three service test point indication, Pa
P dynamometer range, u
14.3.4 Absolute positive test method
) Use true image data and industry approval data to verify: point will be the pressure optical value or point before the approach 1172
) minimum value. This error verification is carried out according to Article 14.3.2. e) The basic error calculation of the value is carried out according to Article 14.3.3. 4.3.5 Differential pressure drop test method
a Compensated pressure zero error test
Connect the high positive (100) and low pressure ends (100) of the one-way single pressure or double differential pressure gauge, apply 25%, 50%, 1(% of the pressure in the question price method, and after the system is stabilized, collect 3 positive and zero indications respectively, and continue to perform 3 times. The static opening and closing error should meet the requirements of Section 6. Single-door pressure gauge
The low non-end (L) of the pressure gauge is suitable for the atmosphere, and the back (H) is connected to the inspection device and the indication is directly connected. The basic design is set as J<.3.2, and the error calculation is carried out according to Section 14.3.3. Double-door pressure test|| tt||First, connect the low normal (L) channel to the atmosphere, and then connect the commercial end (H) to the control meter: then change the commercial front (H) to the air, and the low pressure end (1.) is connected to the calibration device. The basic value of the calibration is selected in Article 14.3.2, and the value is calculated in the middle of the error point (4.3.3). 15
National social error stability
The return error can be calculated by walking back to the technical error calibration. The calibration positive force timing is arranged at the same calibration point 1 times, but the absolute value of the difference between the positive and negative is in line with the requirements of Article 5. 16 Insulation resistance calibration
The micro-open position of the sub-pressure meter is connected, and the rated direct voltage is 500V The insulation resistance is measured between the power supply terminal and the housing, and the reading is taken after the measurement is 10% of the measurement point. The absolute resistance meets the requirements of Section 7: 5. Processing of verification rate and verification cycle
I After the pressure is determined, those that meet the technical requirements of this regulation are qualified and will be issued a "verification certificate"; those that do not meet the technical requirements of this regulation in one technical index will be unqualified and will be issued a "verification notice". The inspection period can be determined according to the environmental conditions and the degree of use, generally 3 months to 1 year, and the longest is less than 1 year.
Deletion 1 Digital pressure gauge verification record format
Determination period
Location of the agent
Central filter station
Emperor's scale of five classics
Determine the permission to identify
External blood generation
Blood electricity control
Small value operation
Regular price delivery
Practice electricity type
External standard inspection value
Anchuan Science
·First inspection
Electrical effect voltage inspection
Qualification date
Inspection certificate back format
Inspection results
Flow path value
Set thermal objects
Appendix 3
Inspection result notice back format
Determination results
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